The essential oil of Cymbopogon martinii was tested for its potency as a botanical pesticide to protect stored wheat (Triticum aestivum) and gram (garbanzo bean, Cicer arietinum) from insect infestation. The C. martinii oil was potent as a fumigant in stored gram. The oil was an effective repellent against the beetles Callosobruchus chinensis and Tribolium castaneum. Geraniol, the major component of the oil, was not as effective as the oil itself. C. martinii oil significantly affected oviposition, adult development, and mortality of C. chinensis in cow peas (Vigna unguiculata). The C. martinii oil when used as fumigant did not affect viability, germination, and seedling growth of gram. Because of its insecticidal and semiochemical nature, the oil could be used as an alternative to synthetic pesticides in an integrated pest management program to protect stored food commodities.